Several years of development and testing have resulted in a simplified human blood lysing solution comprising distilled water, 1% Rhozyme, and 0.5% Tween 20. This new solution lyses erythrocytes, kills phagocytes and releases contained bacteria, and reduces the viscosity of the blood. The latter effect is necessary to permit filtration without filter clogging. The new lysing solution has been shown to be non-injurious over two hours time to all bacterial pathogens tested, including the one most sensitive to the former Triton X-100 based solution, i.e., Neisseria meningitidis. The study now is directed to testing, by lysis-filtration, large series of blood samples from patients, for bacterial recovery, in direct comparison with conventional blood culture techniques. During the same period, animal experiments will be done (in rabbits), creating low-grade septicemia and then testing the relative bacterial recovery of lysis-filtration culture versus conventional culture.